18/09/2021
Here's some interesting info about the lake and water level straight from Dominion Energy.
Dominion Virginia Power built Lake Anna and the Waste Heat Treatment Facility (WHTF) in the late 1960s to provide cooling for the North Anna Power Station. When the station is at full operation, about 2 million gallons per minute of water will pass through the station. The water level in Lake Anna fluctuates above or below the normal lake level elevation of 250 feet above mean sea level (MSI). Normal fluctuations experienced to date have been between 249 feet and 251 feet, however maximum water levels of 255 feet or low water levels of 242 feet could be experienced during extreme conditions. Dominion is required by regulatory permits to discharge normally at least 40 standard cubicfeet per second (scfs) from the spillway. The discharge ow will be increased as necessary following precipitation to return Lake Annalevel to 250 feet. The discharge ow will be reduced to 20 scfs, in accordance with regulatory permits, if Lake Anna level decreases to 248 feet. The discharge flow is continuously monitored and adjusted as necessary by full-time spillway operators. North Anna Power Station uses water from Lake Anna to condense steam back into water inside the station. The water is released into the WHTF slightly warmer than when it was taken. The discharged water cools to ambient temperatures as it ows through a series of private lagoons and is returned to Lake Anna. During the winter months, two recirculating pumps are turned off and the discharge of the other six pumps may be throttled for cold water operations. This results in a seasonal WHTF level decrease of about 8 inches.
The North Anna Dam was built across the North Anna River and is 5,000 feet long and 90 feet high. The spillway is designed to discharge water from Lake Anna into the river. Spillway operators control the flow of water through the spillway to maintain water level at 250 feet above msl.
